Most definitely more than one dying star. Think firstly about how the solar nebula collapsed nearly 10 Gyr after the Big Bang.
The most massive stars have lifetimes of a few million years at most, producing nearly all elements up to Fe and a good number beyond from the r-process, and s-process to much lesser degree. Hundreds of millions of these stars cross-pollinated the Milky Way over billions of years and would eventually contribute to the solar nebula. Stars that are less massive, ones that become AGB stars are the majority of s-process environments in the universe. Stars up to 10 solar masses reach the AGB branch, meaning that lifetimes of these stars can be as low as several-dozen million years. This probably means that millions of these stars contributed to the solar nebula as well.
This doesn't even consider all of the nuclei created by stellar remnants such as Type Ia supernovae and neutron star mergers and other processes.
When you hear that statement the atoms in your left hand came from a different star from the ones in your right hand, it's more realistic to say that nearly every non H and He atom in your body most likely all came from different stars.